Regulation of airflow and performance in information handling systems after fan failure

ABSTRACT

A fan control subsystem may control a plurality of fans in an information handling system to cool the information handling system. The fan control subsystem may determine a fan importance factor for each of the plurality of fans based on the presence and thermal priority ratings of one or more thermal components located in a respective thermal region associated with each of the plurality of fans. Upon detecting a failure of one of the plurality of fans, the fan control subsystem may regulate airflow within the information handling system based on the fan importance factors determined for the fans.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/575,845 filed Dec. 18, 2014, the contents of which is incorporated byreference herein.

BACKGROUND

Field of the Disclosure

This disclosure relates generally to information handling systems andmore particularly to regulating airflow and performance in aninformation handling system after fan failure.

Description of the Related Art

As the value and use of information continues to increase, individualsand businesses seek additional ways to process and store information.One option available to users is information handling systems. Aninformation handling system generally processes, compiles, stores,and/or communicates information or data for business, personal, or otherpurposes thereby allowing users to take advantage of the value of theinformation. Because technology and information handling needs andrequirements vary between different users or applications, informationhandling systems may also vary regarding what information is handled,how the information is handled, how much information is processed,stored, or communicated, and how quickly and efficiently the informationmay be processed, stored, or communicated. The variations in informationhandling systems allow for information handling systems to be general orconfigured for a specific user or specific use such as financialtransaction processing, airline reservations, enterprise data storage,or global communications. In addition, information handling systems mayinclude a variety of hardware and software components that may process,store, and communicate information and may include one or more computersystems, data storage systems, and networking systems.

In various information handling systems, the information handling systemmay cool or otherwise regulate a temperature of itself and itscomponents. One or more fans may be used to help cool the informationhandling system by providing airflow to the information handling systemand the components therein.

SUMMARY

In one aspect, a disclosed method for regulating airflow in aninformation handling system may involve determining fan importancefactors of a first and a second fan respectively associated with a firstand a second thermal region of an information handling system. The fanimportance factors may be based on a presence and on a thermal priorityrating of a first and a second thermal component in the respectivethermal regions. The method may further include detecting a failure ofthe first fan by the fan control subsystem. In response to detecting thefailure of the first fan, the method may further include regulatingairflow in the information handling system based on the first and/or thesecond fan importance factors.

Other disclosed aspects include an article of manufacture including amachine-readable medium having instructions that, when read by aprocessor, cause the processor to determine a first and a second fanimportance factor for first and second fans, respectively, in aninformation handling system. The instructions may then cause theprocessor to detect a failure of the first fan, and, in response todetecting the failure, to regulate airflow in the information handlingsystem based on the first and/or the second fan importance factors.Other disclosed aspects include an information handling system thatregulates its own airflow using systems and methods described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and itsfeatures and advantages, reference is now made to the followingdescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a block diagram of selected elements of an embodiment of aninformation handling system;

FIG. 2 is a block diagram of selected elements of an embodiment of aninformation handling system cooled by a plurality of fans;

FIG. 3 is a block diagram of selected elements of an embodiment of a fancontrol subsystem communicatively coupled with a plurality of fans;

FIG. 4A is a table representative of exemplary information that may beused by a fan control subsystem to determine fan importance factors of aplurality of fans;

FIG. 4B is a table representative of exemplary information that may beused by a fan control subsystem to determine fan importance factors of aplurality of fans;

FIG. 4C is a table representative of exemplary information that may beused by a fan control subsystem to determine fan importance factors of aplurality of fans; and

FIG. 5 is a flowchart depicting selected elements of an embodiment of amethod for regulating airflow and performance in an information handlingsystem after fan failure is detected.

DESCRIPTION OF PARTICULAR EMBODIMENT(S)

In the following description, details are set forth by way of example tofacilitate discussion of the disclosed subject matter. It should beapparent to a person of ordinary skill in the field, however, that thedisclosed embodiments are exemplary and not exhaustive of all possibleembodiments.

Throughout this disclosure, a hyphenated form of a reference numeralrefers to a specific instance of an element and the un-hyphenated formof the reference numeral refers to the element generically orcollectively. Thus, as an example (not shown in the drawings), widget“12-1” refers to an instance of a widget class, which may be referred tocollectively as widgets “12” and any one of which may be referred togenerically as a widget “12”. In the figures and the description, likenumerals are intended to represent like elements.

For the purposes of this disclosure, an information handling system mayinclude an instrumentality or aggregate of instrumentalities operable tocompute, classify, process, transmit, receive, retrieve, originate,switch, store, display, manifest, detect, record, reproduce, handle, orutilize various forms of information, intelligence, or data forbusiness, scientific, control, entertainment, or other purposes. Forexample, an information handling system may be a server, a personalcomputer, a PDA, a consumer electronic device, a network storage device,or another suitable device and may vary in size, shape, performance,functionality, and price. The information handling system may includememory, one or more processing resources such as a central processingunit (CPU) or hardware or software control logic. Additional componentsor the information handling system may include one or more storagedevices, one or more communications ports for communicating withexternal devices as well as various input and output (I/O) devices, suchas a keyboard, a mouse, and a video display. The information handlingsystem may also include one or more buses operable to transmitcommunication between the various hardware components.

Additionally, the information handling system may include firmware forcontrolling and/or communicating with, for example, hard drives, networkcircuitry, memory devices, I/O devices, and other peripheral devices. Asused in this disclosure, firmware includes software embedded in aninformation handling system component used to perform predefined tasks.Firmware is commonly stored in non-volatile memory, or memory that doesnot lose stored data upon the loss of power. In certain embodiments,firmware associated with an information handling system component isstored in non-volatile memory that is accessible to one or moreinformation handling system components. In the same or alternativeembodiments, firmware associated with an information handling systemcomponent is stored in non-volatile memory that is dedicated to andcomprises part of that component.

For the purposes of this disclosure, computer-readable media may includean instrumentality or aggregation of instrumentalities that may retaindata and/or instructions for a period of time. Computer-readable mediamay include, without limitation, storage media such as a direct accessstorage device (e.g., a hard disk drive or floppy disk), a sequentialaccess storage device (e.g., a tape disk drive), compact disk, CD-ROM,DVD, random access memory (RAM), read-only memory (ROM), electricallyerasable programmable read-only memory (EEPROM), and/or flash memory(SSD); as well as communications media such wires, optical fibers,microwaves, radio waves, and other electromagnetic and/or opticalcarriers; and/or any combination of the foregoing.

Particular embodiments are best understood by reference to FIGS. 1-5wherein like numbers are used to indicate like and corresponding parts.

Turning now to the drawings, FIG. 1 illustrates a block diagramdepicting selected elements of an embodiment of information handlingsystem 100. In one embodiment, information handling system 100 may beconfigured to regulate its own airflow and/or to regulate airflow withinanother information handling system. Also shown with informationhandling system 100 are external or remote elements, namely, network 155and network storage resource 170.

As shown in FIG. 1, components of information handling system 100 mayinclude, but are not limited to, processor subsystem 120, which maycomprise one or more processors, and system bus 121 that communicativelycouples various system components to processor subsystem 120 including,for example, memory subsystem 130, I/O subsystem 140, local storageresource 150, and network interface 160. System bus 121 may represent avariety of suitable types of bus structures, e.g., a memory bus, aperipheral bus, or a local bus using various bus architectures inselected embodiments. For example, such architectures may include, butare not limited to, Micro Channel Architecture (MCA) bus, IndustryStandard Architecture (ISA) bus, Enhanced ISA (EISA) bus, PeripheralComponent Interconnect (PCI) bus, PCI Express (PCIe) bus, HyperTransport(HT) bus, and Video Electronics Standards Association (VESA) local bus.

In FIG. 1, network interface 160 may be a suitable system, apparatus, ordevice operable to serve as an interface between information handlingsystem 100 and a network 155. Network interface 160 may enableinformation handling system 100 to communicate over network 155 using asuitable transmission protocol and/or standard, including, but notlimited to, transmission protocols and/or standards enumerated belowwith respect to the discussion of network 155. In some embodiments,network interface 160 may be communicatively coupled via network 155 tonetwork storage resource 170. Network 155 may be implemented as, or maybe a part of, a storage area network (SAN), personal area network (PAN),local area network (LAN), a metropolitan area network (MAN), a wide areanetwork (WAN), a wireless local area network (WLAN), a virtual privatenetwork (VPN), an intranet, the Internet or another appropriatearchitecture or system that facilitates the communication of signals,data and/or messages (generally referred to as data). Network 155 maytransmit data using a desired storage and/or communication protocol,including, but not limited to, Fibre Channel, Frame Relay, AsynchronousTransfer Mode (ATM), Internet protocol (IP), other packet-basedprotocol, small computer system interface (SCSI), Internet SCSI (iSCSI),Serial Attached SCSI (SAS) or another transport that operates with theSCSI protocol, advanced technology attachment (ATA), serial ATA (SATA),advanced technology attachment packet interface (ATAPI), serial storagearchitecture (SSA), integrated drive electronics (IDE), and/or anycombination thereof. Network 155 and its various components may beimplemented using hardware, software, or any combination thereof. Incertain embodiments, system 100 and network 155 may be included in arack domain.

As depicted in FIG. 1, processor subsystem 120 may comprise a system,device, or apparatus operable to interpret and/or execute programinstructions and/or process data, and may include a microprocessor,microcontroller, digital signal processor (DSP), application specificintegrated circuit (ASIC), or another digital or analog circuitryconfigured to interpret and/or execute program instructions and/orprocess data. In some embodiments, processor subsystem 120 may interpretand/or execute program instructions and/or process data stored locally(e.g., in memory subsystem 130 and/or another component of physicalhardware 102). In the same or alternative embodiments, processorsubsystem 120 may interpret and/or execute program instructions and/orprocess data stored remotely (e.g., in a network storage resource).

Also in FIG. 1, memory subsystem 130 may comprise a system, device, orapparatus operable to retain and/or retrieve program instructions and/ordata for a period of time (e.g., computer-readable media). As shown inthe example embodiment of FIG. 1, memory subsystem 130 storesuser-personalized wake policy 132, which may include instructionsexecutable by processor subsystem 120 to implement the methods describedherein. It is noted that in different embodiments, user-personalizedwake policy 132 may be stored at network storage resource 170 and may beaccessed by processor subsystem 120 via network 155 Memory subsystem 130may comprise random access memory (RAM), electrically erasableprogrammable read-only memory (EEPROM), a PCMCIA card, flash memory,magnetic storage, opto-magnetic storage, and/or a suitable selectionand/or array of volatile or non-volatile memory that retains data afterpower to its associated information handling system, such as informationhandling system 100, is powered down.

In FIG. 1, local storage resource 150 may comprise computer-readablemedia (e.g., hard disk drive, floppy disk drive, CD-ROM, and/or othertype of rotating storage media, flash memory, EEPROM, and/or anothertype of solid state storage media) and may be generally operable tostore instructions and/or data. For example, local storage resource 150may store executable code in the form of program files that may beloaded into memory subsystem 130 for execution, such asuser-personalized wake policy 132. In information handling system 100,I/O subsystem 140 may comprise a system, device, or apparatus generallyoperable to receive and/or transmit data to/from/within informationhandling system 100. I/O subsystem 140 may represent, for example, avariety of communication interfaces, graphics interfaces, videointerfaces, user input interfaces, and/or peripheral interfaces. Incertain embodiments, I/O subsystem 140 may comprise a touch panel and/ora display adapter. The touch panel (not shown) may include circuitry forenabling touch functionality in conjunction with a display (not shown)that is driven by display adapter (not shown).

Referring now to FIG. 2, selected elements of an embodiment of aninformation handling system 200 are illustrated for regulating airflowwithin information handling system 200 in order to cool certain elementsshown. FIG. 2 shows a component layout view of certain exemplarycomponents of information handling system 200. The components shown inFIG. 2 are not drawn to scale and information handling system 200 maycontain additional or fewer components than the components shown in FIG.2. Components of information handling system 200 may be interconnectedwith each other as well as with other components not shown in FIG. 2.However, connections between components are omitted in FIG. 2 fordescriptive clarity. In FIG. 2, information handling system 200 mayimplement an embodiment of information handling system 100 describedabove with respect to FIG. 1.

As shown in FIG. 2, information handling system 200 may include circuitboard 202. Circuit board 202 may be contained within chassis 204.Chassis 204 may be enclosed in any suitable manner. For example, chassis204 may include front panel 206-1 and back panel 206-2. Front panel206-1 and back panel 206-2 may include one or more input/outputconnectors (not shown) allowing information handling system 200 tointerconnect with additional information handling systems and/or otherdevices (not shown). To cool information handling system 200, airflow208 may be directed over circuit board 202. Such airflow may be made ina suitable direction. For example, airflow 208 may be made in adirection from front panel 206-1 toward back panel 206-2. Airflow 208may be generated by a plurality of fans 210 (e.g., fans 210-1 through210-6) residing within information handling system 200. In oneembodiment, each fan 210 may be associated with a respective thermalregion 212 (e.g., thermal regions 212-1 through 212-6) of circuit board202. Each thermal region 212 may include one or more thermal componentssuch as high priority components 220, medium priority components 222,and low priority components 224. For convenience, certain thermalcomponents shown within information handling system 200 are labeled witha designator indicating a thermal region 212 to which the thermalcomponents belong. For example, two high priority components 220 shownwithin information handling system 200 are labeled as 220-2(corresponding to thermal region 212-2) and 220-5 (corresponding tothermal region 212-5). For convenience of description, certain thermalcomponents in FIG. 2 are associated with exactly one thermal region 212.It is noted, however, that other thermal components may be associatedwith more than one thermal region 212. For example, small dynamic card226, medium dynamic card 228, and large dynamic card 230 may beassociated with more than one thermal region 212. For example, largedynamic card 230 is associated with thermal regions 212-1, 212-2, and212-3.

As shown in FIG. 2, information handling system 200 and/or variouscomponents included therein may be contained within chassis 204. Chassis204 of information handling system 200 may include any case or enclosureadapted to hold or encompass information handling system 200 or variouscomponents of information handling system 200. Chassis 204 may beconstructed from steel, aluminum, plastic, glass, any other suitablematerial, or any combination of these. Certain types of informationhandling systems may be well suited to particular types of chassis. Forexample, information handling system 200 may be a server module and maythus be well suited to a rack-type chassis. Chassis 204 may be arack-type chassis adapted to fit alongside other server modulescontained in similar rack-type chassis within a frame or rack adapted tohold multiple server modules. In a rack setup, each server module may beindependent or interdependent. Thus, an information handling system mayexist on one server module as shown in FIG. 2, or an informationhandling system may exist across multiple server modules in a rack ormany server modules in multiple racks (not shown).

In some examples, a plurality of fans may be used to cool a singleinformation handling system. For example, as shown in FIG. 2, six fans210 are used to cool information handling system 200. As such,information handling system 200 may be subdivided into a plurality ofthermal regions 212, wherein each thermal region is associated with oneor more fans 210. Thermal regions may be discrete or may overlap.Thermal regions may be distinct and well-defined or indistinct andloosely defined. For example, FIG. 2 shows six thermal regions 212situated as parallel strips along circuit board 202, each thermal region212 being associating with one fan 210. Although FIG. 2 shows thermalregions 212 as being situated as parallel strips along circuit board202, it will be appreciated that thermal regions 212 may be situated inany suitable way. For example, in some embodiments, four thermal regionsmay be situated in four quadrants of a circuit board (not shown). Inother embodiments, a thermal region may include a server moduleassociated with an information handling system encompassing multipleserver modules in one or more racks.

As shown in FIG. 2, each thermal region 212 on circuit board 202 mayinclude one or more thermal components cooled by a fan 210 that isassociated with the particular thermal region 212. For example, asshown, thermal region 212-1 may include at least a portion of threethermal components. Thermal region 212-1 may include medium prioritycomponent 222-1. Thermal region 212-1 may also include low prioritycomponent 224-1. Thermal region 212-1 may also include a portion oflarge dynamic card 230.

As shown, thermal region 212-2 may include at least a portion of threethermal components. Thermal region 212-2 may include high prioritycomponent 220-2. Thermal region 212-2 may also include low prioritycomponent 224-2. Thermal region 212-2 may also include a portion oflarge dynamic card 230.

As shown, thermal region 212-3 may include at least a portion of fourthermal components. Thermal region 212-3 may include medium prioritycomponent 222-3. Thermal region 212-3 may also include low prioritycomponent 224-3. Thermal region 212-3 may also include a portion ofmedium dynamic card 228. Thermal region 212-3 may also include a portionof large dynamic card 230.

As shown, thermal region 212-4 may include at least a portion of threethermal components. Thermal region 212-4 may include medium prioritycomponent 222-4. Thermal region 212-4 may also include a portion ofmedium dynamic card 228. Thermal region 212-4 may also include lowpriority component 224-4.

As shown, thermal region 212-5 may include at least a portion of fourthermal components. Thermal region 212-5 may include high prioritycomponent 220-5. Thermal region 212-5 may also include a portion ofmedium dynamic card 228. Thermal region 212-5 may also include lowpriority component 224-5. Thermal region 212-5 may also include aportion of small dynamic card 226.

Finally, as shown, thermal region 212-6 may include at least a portionof three thermal components. Thermal region 212-6 may include mediumpriority component 222-6. Thermal region 212-6 may also include lowpriority component 224-6. Thermal region 212-6 may also include aportion of small dynamic card 226.

In FIG. 2, airflow 208 may be controlled and/or regulated by fans 210.Fans 210 may include any device capable of directing airflow 208, forexample, a computer fan. Fans 210 may be configured to actively coolinformation handling system 200 by directing airflow 208 across asurface of circuit card 202. For example, airflow 208 may coolinformation handling system 200 by drawing heat away from variousthermal components of information handling system 200. In some examples,a particular fan may be associated with a particular thermal componentof information handling system 200. For example, a fan may be attachedto a heat sink of a particular component such as a processor (notshown). Fans 210 may also be associated with particular thermal regions212 of an information handling system. For example, as shown in FIG. 2,fan 210-1 is associated with thermal region 212-1, fan 210-2 isassociated with thermal region 212-2, and so forth. In certain examples,fans may also be associated with the information handling systemgenerally. For example, a fan may be associated with one server modulecontained in a rack containing several server modules (not shown). Asshown, fans 210 are included within chassis 204 of information handlingsystem 200. In other examples, however, fans may be included outside achassis or may be attached to a chassis of an information handlingsystem. To generate airflow 208, fans 210 may draw relatively cool airfrom outside the chassis (e.g., ambient air near front panel 206-1) intothe chassis and may expel relatively warm air from inside the chassisback out of the chassis (e.g., near back panel 206-2).

Fans 210 may direct airflow 208 to move across thermal components withininformation handling system 200 to cool information handling system 200.Thermal components may include any components within informationhandling system 200 that may be cooled by airflow 208. For example,among the thermal components illustrated in FIG. 2 are circuit board202, chassis 204, high priority components 220, medium prioritycomponents 222, low priority components 224, small dynamic card 226,medium dynamic card 228, and large dynamic card 230. In certainexamples, thermal components within information handling system 200 mayinclude processors, memory devices, computer-readable media, buses,communication interface cards, etc. Thermal components may consumepower, causing the thermal components to heat up. When fans 210 directairflow 208 to move across circuit board 202 and the other thermalcomponents disposed thereon, heat may be drawn away from informationhandling system 200, cooling information handling system 200.Accordingly, using airflow 208 to cool information handling system 200,fans 210 may regulate the temperature of information handling system200.

Referring now to FIG. 3, a block diagram of selected elements of anembodiment of a fan control subsystem 300 is illustrated. FIG. 3 is aschematic illustration and is not drawn to scale. In FIG. 3, fan controlsubsystem 300 may control fans 210 to regulate airflow 208 to cool orotherwise regulate the temperature of information handling system 200.In certain embodiments, fan control subsystem 300 may be integrated withor included within information handling system 200. In otherembodiments, fan control subsystem 300 may be independent frominformation handling system 200. For example, fan control subsystem 300may be integrated with an information handling system tasked withcooling one or more other information handling systems includinginformation handling system 200. As shown, fan control subsystem 300includes processor 302. Processor 302 may be implemented by any type ofprocessor, such as a microcontroller, a digital signal processor (DSP),a field-programmable gate-array, an application-specific integratedcircuit, digital or analog circuitry, etc. Processor 302 may becommunicatively coupled to memory 304. Memory 304 may be implemented bycomputer-readable memory media. Memory 304 may encompass persistent andvolatile media, fixed and removable media, and magnetic andsemiconductor media, among others. Memory 304 is operable to storeinstructions, data, or both. Memory 304 may include or store sets orsequences of instructions executable by processor 302, as well as otherinformation, such as data related to fan control, as disclosed herein.As shown, memory 304 stores firmware 306, which may include executableinstructions to implement at least a portion of the functionalitydescribed herein with respect to fan control.

In embodiments where fan control subsystem 300 is integrated with orincluded within information handling system 200, certain components offan control subsystem 300 may be associated with or the same ascomponents of information handling system 200, described above inrelation to FIGS. 1 and 2. For example, processor 302 of fan controlsubsystem 300 may be associated with or implemented by high prioritycomponents 220-2 and/or 220-5 (see FIG. 2). In addition, high prioritycomponents 220-2 and/or 220-5 may also be associated with processorsubsystem 120 (see FIG. 1) within information handling system 200.Accordingly, information handling system 200 may self-regulate its owntemperature by using fan control subsystem 300, integrated withininformation handling system 200, to cool information handling system200.

As shown in FIG. 3, fans 210 are communicatively coupled to fan controlsubsystem 300. As such, fan control subsystem 300 may control and/orotherwise communicate with fans 210 and may thereby regulate thetemperature of information handling system 200 (see FIG. 2). In certainembodiments, fan control subsystem 300 may control fans 210 according torespective fan importance factors. A fan importance factor may beassociated with each of fans 210. The fan importance factor associatedwith a particular fan signifies a relative importance of the particularfan as compared to other fans. Specifically, if a first fan has a higherfan importance factor than a second fan, the first fan may be consideredmore important to cooling the information handling system than thesecond fan. For example, the first fan may be considered more importantthan the second fan because the thermal region associated with the firstfan may be more difficult to cool or may include thermal components thatare more critical to the information handling system as compared to thethermal region associated with the second fan.

Fan control subsystem 300 may determine the fan importance factors foreach of fans 210 in any suitable way. In some examples, a fan importancefactor may be predetermined (e.g., by a designer, user, technician,etc.) and preprogrammed into fan control subsystem 300, such as intomemory 304. Thus, fan control subsystem 300 may determine the fanimportance factor by retrieving the fan importance factor from memory304. In other examples, fan control subsystem 300 may determine a fanimportance factor of a fan by computing the fan importance factor basedon a presence of one or more thermal components in a thermal regionassociated with the fan. Fan control subsystem 300 may also compute thefan importance factor based on respective thermal priority ratings ofthe one or more thermal components present in the thermal regionassociated with the fan, as will be described in more detail below. Forexample, if a fan is associated with a thermal region that has severalthermal components with high thermal priority ratings, the fan may be ofrelatively high importance for cooling the information handling systemand may thus have a relatively high fan importance factor.

A thermal priority rating of a thermal component may include any index,score, etc. associated with a priority level for cooling the thermalcomponent within an information handling system. For example, a thermalcomponent with a high thermal priority rating may be important or evencritical to proper operation of the information handling system.Additionally or alternatively, the thermal component with the highthermal priority rating may be particularly difficult to cool due tohigh power consumption and heat or due to the placement of the thermalcomponent in the layout of the information handling system. In otherexamples, a thermal component with a low thermal priority rating may beless important to proper functionality of the information handlingsystem. Additionally or alternatively, the thermal component with thelow thermal priority rating may be relatively trivial to cool.

As such, a thermal priority rating may be determined by any suitablefactors or parameters affecting the cooling of the thermal component. Incertain examples, a thermal priority rating may be based at least inpart on how much power the thermal component consumes. For example, athermal component that consumes a large amount of power may have anincreased thermal priority rating. Similarly, a thermal component thatconsumes a small amount of power may have a decreased thermal priorityrating. In other examples, a thermal priority rating may be based atleast in part on a maximum temperature parameter specified for properoperation of the thermal component. For example, a thermal component notcapable of operating properly at a high maximum temperature may have anincreased thermal priority rating. Similarly, a thermal component thatis designed to operate properly at high maximum temperatures may have adecreased thermal priority rating. In yet other examples, a thermalpriority rating may be based at least in part on a proximity of thethermal component to one or more fans in the layout of the informationhandling system. For example, a thermal component far away from the fansmay have an increased thermal priority rating. Similarly, a thermalcomponent near the fans may have a decreased thermal priority rating. Inyet other examples, a thermal priority rating may be based at least inpart on a proximity of the thermal component to one or more otherthermal components. For example, a thermal component proximate otherthermal components may have an increased thermal priority rating,particularly if the other thermal components themselves have highthermal priority ratings. Similarly, a thermal component isolated fromother thermal components may have a decreased thermal priority rating.In yet other examples, a thermal priority rating may be based at leastin part on the importance of the thermal component for desired operationof the information handling system. For example, a thermal componentthat is crucial to operations of the information handling system (e.g.,a processor) may have an increased thermal priority rating. Similarly, athermal component that is less important to operations of theinformation handling system may have a decreased thermal priorityrating. In yet other examples, a thermal priority rating may be based atleast in part on the availability of individual active or passive meansfor cooling the thermal component such as a heat sink or individual fanassociated with the thermal component. For example, a thermal componentthat relies solely on system fans (e.g., fans 210) to be cooled may havean increased thermal priority rating. Similarly, a thermal componentthat includes a heat sink and/or an individual fan may have a decreasedthermal priority rating. In yet other examples, a thermal priorityrating may be based at least in part on a power density of the thermalcomponent. For example, a thermal component with a high power densitymay have an increased thermal priority rating. Similarly, a thermalcomponent with a low power density may have a decreased thermal priorityrating. In yet other examples, a thermal priority rating may be based atleast in part on a surface area of the thermal component. For example, athermal component with a large surface area may have an increasedthermal priority rating. Similarly, a thermal component with a smallsurface area may have a decreased thermal priority rating. In variousother examples, thermal priority ratings may be based on one or more ofthe factors described above and/or on any other factor or parameterassociated with the thermal component that may affect how importantand/or difficult the thermal component is to cool.

Thermal priority ratings may be calculated and associated with thermalcomponents in any suitable way. In certain examples, thermal priorityratings may be predetermined (e.g., by a designer, user, technician,etc.) and preprogrammed into the fan control subsystem, such as intomemory 304 of fan control subsystem 300. In other examples, thermalpriority ratings may be determined for certain components automaticallyand/or dynamically by information handling system 200 or fan controlsubsystem 300 without human intervention. Referring to FIG. 2, variousfactors may be considered in determining whether high priority component220-2 or medium priority component 222-1 is a higher priority to cool.For example, although the distance between medium priority component222-1 and fan 210-1 may be greater than the distance between highpriority component 220-2 and fan 210-2, high priority thermal component220-2 may be a more crucial component, such as a processor, and/or maygenerate more heat. Considering several parameters related to coolinghigh priority component 220-2 and medium priority component 222-1 inthis way, it may be determined that a higher thermal priority ratingshould be associated with high priority component 220-2 than with mediumpriority component 222-1. In various embodiments, more or fewerparameters may be considered and weighed in any manner that suits thevarious embodiments.

Fan control subsystem 300 may determine the presence and location ofthermal components of information handling system 200 in any suitableway. For example, board layout information indicative of the presenceand location of each thermal component may be automatically detected orpreprogrammed and stored in memory 304 where the board layoutinformation may be accessed by fan control subsystem 300. Additionally,information handling system 200 may solicit information indicative ofthe presence and location of thermal components from a person (e.g., adesigner, a user, a technician, etc.), who may input the informationinto memory 304 to be accessed by fan control subsystem 300. In variousembodiments, the presence and location of certain thermal components maybe preprogrammed while the presence and location of other thermalcomponents may be automatically detected by fan control subsystem 300.For example, high priority components 220, medium priority components222, and low priority components 224 may be fixed to circuit board 202,and may be represented by preprogrammed information stored in memory304. Meanwhile, small dynamic card 226, medium dynamic card 228, andlarge dynamic card 230 may be transitory or dynamic. For example,dynamic cards 226, 228, and 230 may be PCI Express cards. As such,dynamic cards 226, 228, and 230 may be installed onto or removed fromcircuit board 202. Additionally, a particular socket adapted to accept alarge dynamic card such as large dynamic card 230 may also accept asmall dynamic card such as small dynamic card 226. Accordingly,determining the presence and location of all the thermal componentswithin a thermal region 212 may include receiving preprogrammedinformation about certain thermal components (e.g., components 220, 222,and 224) and detecting information about other thermal components (e.g.,dynamic cards 226, 228, and 230).

Based on information indicative of the thermal priority rating andpresence of each thermal component in each thermal region 212 ofinformation handling system 200, fan control subsystem 300 may determinea fan importance factor associated with each fan 210 to indicate theimportance of each fan 210 relative to the other fans 210. For example,referring to information handling system 200 in FIG. 2, thermal region212-1 may be thermally identical to thermal region 212-2 except thatthermal region 212-1 includes medium priority component 222-1 whilethermal region 212-2 includes high priority component 220-2. Becausehigh priority component 220-2 may be more difficult to cool than mediumpriority component 222-1, as described above in relation to thermalpriority ratings, fan control subsystem 300 may determine a higher fanimportance factor for fan 210-2 than for fan 210-1.

Specifically, fan control subsystem 300 may determine that thermalregion 212-1 includes at least a portion of three thermal components:medium priority component 222-1, low priority component 224-1, and largedynamic card 230. Fan control subsystem 300 may further determine thatmedium priority component 222-1 has a moderate thermal priority rating,that low priority component 224-1 has a low thermal priority rating, andthat large dynamic card 230 has a low thermal priority rating. Based onthe presence and the thermal priority ratings of medium prioritycomponent 222-1, low priority component 224-1, and large dynamic card230, fan control subsystem 300 may determine a fan importance factor forfan 210-1 associated with thermal region 212-1. Fan control subsystem300 may also determine that thermal region 212-2 includes at least aportion of three thermal components: high priority component 220-2, lowpriority component 224-2, and large dynamic card 230. Fan controlsubsystem 300 may further determine that high priority component 220-2has a high thermal priority rating, for example, a thermal priorityrating higher than the thermal priority rating of medium prioritycomponent 222-1. Fan control subsystem 300 may further determine thatlow priority component 224-2 has an equal thermal priority rating to lowpriority component 224-1. Accordingly, fan control subsystem 300 maydetermine a fan importance factor for fan 210-2 associated with thermalregion 212-2 that is higher than the fan importance factor of fan 210-1associated with thermal region 212-1. The higher fan importance factorof fan 210-2 reflects the presence of high priority component 220-2,which is a higher priority to cool than medium priority component 222-1.Accordingly, the higher fan importance factor of fan 210-2 indicatesthat fan 210-2 is more important than fan 210-1 for cooling informationhandling system 200.

FIGS. 4A, 4B, and 4C illustrate various tables representative ofinformation that may be used by fan control subsystem 300 to determinefan importance factors of each of fans 210. For example, fan controlsubsystem 300 may receive or detect the information represented in FIGS.4A, 4B, and 4C, and may store the information in memory 304.Subsequently, fan control subsystem 300 may use the information from oneor more of FIGS. 4A, 4B, and 4C to determine respective fan importancefactors associated with each of fans 210.

In FIG. 4A, location table 400 shows a table representation indicativeof the presence and location of various thermal components ofinformation handling system 200. Along horizontal axis 402, each of fans210 corresponds to a vertical column. Along vertical axis 404, variousthermal components of information handling system 200 correspond to ahorizontal row. As shown, a mark is placed in each respective row andcolumn where a particular fan 210 is associated with a particularthermal component. For example, because high priority component 220-2 islocated in thermal region 212-2 (see FIG. 2), high priority component220-2 is associated with fan 210-2 and a mark is present in the columnof fan 210-2 and the row of high priority component 220-2.

In FIG. 4B, thermal priority ratings table 410 shows a tablerepresentation indicative of the thermal priority ratings of variousthermal components of information handling system 200. Along verticalaxis 414, various thermal components of information handling system 200correspond to a horizontal row. In column 412, a thermal priority ratingbetween 1 and 10 is shown for each thermal component. For example,because high priority component 220-2 is a high priority to cool, athermal priority rating of 9 is shown for high priority component 220-2.It is noted that thermal priority ratings may be relative to oneanother. In various embodiments, thermal priority ratings may includevalues other than integers between 1 and 10.

In FIG. 4C, fan importance factor table 420 shows a table combininginformation indicative of the presence and location of the variousthermal components of information handling system 200 from locationtable 400 (see FIG. 4A), and information indicative of the thermalpriority ratings of the various thermal components from thermal priorityratings table 410 (see FIG. 4B). Along horizontal axis 422, each of fans210 corresponds to a vertical column. Along vertical axis 424, the samethermal components of information handling system 200 represented intables 400 and 410 each correspond to a horizontal row. As shown, arespective thermal priority rating for each thermal component accordingto thermal priority ratings table 420 is placed in a row and columncorresponding to the location of each thermal component corresponding tolocation table 400. For example, high priority component 220-2 has athermal priority rating of 9 according to thermal priority ratings table420. High priority component 220-2 is located in a thermal regionassociated with fan 210-2 according to location table 400. Therefore, a9 is shown in a cell corresponding to the row for high prioritycomponent 220-2 and the column for fan 210-2.

As shown in FIG. 4C, raw fan importance factor row 426 includes a fanimportance factor corresponding to each of fans 210 equaling a sum totalof the thermal priority ratings listed in each vertical column alonghorizontal axis 422. The fan importance factors shown in raw fanimportance factor row 426 may be referred to as raw fan importancefactors. For example, fan 210-1 is shown with a raw fan importancefactor of 11 because 11 is the sum of the thermal priority ratings ofmedium priority component 222-1 (i.e. 6), low priority component 224-1(i.e. 3), and large dynamic card 230 (i.e. 2).

Normalized fan importance factor row 428 also includes a fan importancefactor corresponding to each of fans 210. As shown, the fan importancefactors in normalized fan importance factor row 428 are derived fromrespective raw fan importance factors from raw fan importance factor row426 by normalizing each raw fan importance factor such that the lowestfan importance factor is equal to 1.00. The fan importance factors shownin normalized fan importance factor row 428 may be referred to asnormalized fan importance factors. For example, because 7, the fanimportance factor corresponding to fan 210-4, is the lowest raw fanimportance factor on raw fan importance factor row 426, each raw fanimportance factor is divided by 7 to derive the normalized fanimportance factors of normalized fan importance factor row 428. Thus,for example, fan 210-1 is shown with a normalized fan importance factorof 1.57 because 1.57 is the approximate quotient of 11 divided by 7.

Relative importance ranking row 430 may include a relative importanceranking corresponding to each of fans 210. As shown, the relativeimportance rankings in relative importance ranking row 430 are derivedfrom respective fan importance factors from raw fan importance factorrow 426 and/or normalized fan importance factor row 428 by ranking eachfan 210 from a most important fan having a highest fan importance factordown to a least important fan having a lowest fan importance factor. Forexample, because fan 210-2 has the highest fan importance factor in rawfan importance factor row 426 and in normalized fan importance factorrow 428, fan 210-2 is ranked with a number 1, indicative that fan 210-2may be the most important fan. Similarly, as shown, fan 210-3 is rankedas the second most important fan, fan 210-5 is ranked as the third mostimportant fan, fans 210-1 and 210-6 are each ranked as the fourth mostimportant fans because fans 210-1 and 210-6 have equal fan importancefactors, and fan 210-4 is ranked as the fifth most important fan. Thus,in information handling system 200, fan 210-4 may be the least importantfan.

In information handling system 200, one or more of fans 210 may fail atany time due to various circumstances. The failure of a fan may bedetrimental to operations and/or performance of information handlingsystem 200. For example, the temperature of one or more thermalcomponents in information handling system 200 may not be properlyregulated after fan failure because airflow to cool the thermalcomponents is reduced. In particular, temperatures of thermal componentsin a thermal region associated with a failed fan may increase untilproper operation and performance of the thermal components is affected.In some examples, a temperature of a thermal component may increaseabove a maximum temperature threshold specified for the thermalcomponent and the thermal component may cease functioning or mayfunction improperly. Accordingly, fan control subsystem 300 may beconfigured to detect a fan failure and, in response, regulate airflow ininformation handling system 200 to minimize negative effects of fanfailure on information handling system 200 until the failed fan may beremedied.

Fan control subsystem 300 may detect a fan failure in any suitable way.For example, fan control subsystem 300 may automatically detect that afan has failed by receiving a signal from the failed fan or by notreceiving expected feedback from the failed fan. A user of informationhandling system 200 may also input information into fan controlsubsystem 300 indicative that a particular fan has failed.

In response to detecting the failure of a fan in information handlingsystem 200, fan control subsystem 300 may regulate airflow 208 ininformation handling system 200 to minimize negative effects of the fanfailure on information handling system 200. In various embodiments, fancontrol subsystem 300 may determine one or more fan importance factorsand/or relative importance rankings for fans 210 as described above inrelation to FIGS. 4A, 4B, and 4C, and may regulate airflow 208 based thefan importance factors and/or relative importance rankings. Variousembodiments of fan control subsystem 300 may present particularlimitations and/or opportunities for regulating airflow 208 by fancontrol subsystem 300. For example, in some embodiments, it may bedesirable that fan control subsystem 300 regulate airflow 208automatically without human intervention. In other embodiments, atechnician may be available to perform a task directed by fan controlsubsystem 300.

Certain information handling systems may include “closed loop” thermalcomponents with independent thermal sensors that may independently orcooperatively control fans within information handling system 200. Incertain examples, a closed loop thermal component may be associated withan individual fan and may be configured to control the individual fan.For example, a closed loop thermal component may directly control anindividual fan mounted on a heat sink attached to the closed loopthermal component(not shown). In other examples, a closed loop thermalcomponent may share control over shared system fans such as fans 210.For example, a closed loop thermal component may share control over fans210 with fan control subsystem 300. Specifically, the closed loopthermal component may cause a fan speed of one of fans 210 to increasebeyond a fan speed directed by fan control subsystem 300. While closedloop thermal components may independently self-regulate theirtemperature at least partially, “open loop” thermal components may becooled only by airflow 208 generated by fans 210. Accordingly, incertain embodiments including both closed loop and open loop thermalcomponents, fan control subsystem 300 may be configured to ignore closedloop thermal components to determine fan importance factors based onlyon open loop thermal components. In other embodiments, both closed loopthermal components and open loop thermal components may be taken intoaccount to determine fan importance factors of fans 210. Still otherembodiments may include only open loop thermal components such that fanimportance factors may be determined based only on the open loop thermalcomponents.

Additionally, certain embodiments of fan control subsystem 300 may haveaccess to additional information about information handling system 200that is not available in all embodiments. For example, fan controlsubsystem 300, as implemented in certain embodiments described in moredetail below, may receive or detect information indicative of a nominalvolumetric airflow associated with cooling information handling system200 when all of fans 210 are operational. Regardless of variationsbetween various embodiments, fan importance factors and relativeimportance rankings for fans may provide valuable insight into airflowin an information handling system and may facilitate various approachesfor efficiently and appropriately regulating and/or optimizing theairflow according to the circumstances of a particular situation.Certain exemplary approaches for regulating airflow are now described.

In certain embodiments, regulating the airflow in response to detectingthat a fan has failed may include directing a user (e.g., a technician,an operator of information handling system 200, etc.) to swap the failedfan with an operational fan, based on fan importance factors and/orrelative importance rankings of the failed fan and the operational fan.Specifically, fan control subsystem 300 may direct the user to swap afailed fan with any operational fan having an equal or lower fanimportance factor than the failed fan. Equivalently, fan controlsubsystem 300 may direct the user to swap the failed fan with anyoperational fan having an equal or higher relative importance ranking asthe failed fan. For example, when fan control subsystem 300 detects thatfan 210-2 fails, fan control subsystem 300 may direct that fan 210-2,the most important fan in information handling system 200 based on thefan importance factor and relative importance ranking of fan 210-2 (seeFIG. 4C), be swapped with fan 210-4, the least important fan ininformation handling system 200 based on the fan importance factor andrelative importance ranking of fan 210-4. In other examples, fan controlsubsystem 300 may determine that, while airflow 208 may be mostoptimized by swapping fan 210-2 with fan 210-4, airflow 208 may still beat least somewhat improved by swapping fan 210-2 with anotheroperational fan 210 having a lower fan importance factor and a higherrelative importance ranking than fan 210-2 (e.g., fans 210-1, 210-3,210-5, or 210-6). Accordingly, fan control subsystem 300 may direct theuser to swap fan 210-2 with an operational fan other than fan 210-4. Incertain embodiments, fan control subsystem 300 may provide a pluralityof options to the user for the fan swapping. For example, fan controlsubsystem 300 may indicate that swapping fan 210-2 with fan 210-4 may bepreferred, but that swapping fan 210-2 with fan 210-1 or with fan 210-6would also be suitable.

When fans other than the most important fan (e.g., fan 210-2) fail,fewer swapping options may be available to improve cooling ininformation handling system 200. For example, when fan 210-1 fails, fancontrol subsystem 300 may recommend swapping fan 210-1 with fan 210-4 orfan 210-6, but may not recommend any other swap because every fan otherthan fan 210-4 has a higher fan importance factor and lower relativeimportance ranking than fan 210-1. Similarly, when fan control subsystem300 detects that fan 210-4—the least important fan 210—fails, fancontrol subsystem 300 may determine that swapping any fan with fan 210-4would serve to inhibit cooling in information handling system 200because the fan importance factor of every operational fan 210 is higherthan the fan importance factor of fan 210-4. Accordingly, fan controlsubsystem 300 may direct the user to not swap fan 210-4 with any otherfan 210 or may not direct the user to do anything.

Fan control subsystem 300 may direct the user to swap fans in anysuitable way. For example, fan control subsystem 300 may provide apop-up dialog box directing the user to physically perform the fanswapping. Additionally or alternatively, fan control subsystem 300 mayprovide an output message or error code directing that the fans beswapped in an event log associated with information handling system 200.

In certain embodiments, regulating the airflow in response to detectingthat a fan has failed may include increasing a fan speed of one or moreoperational fans based on the fan importance factor determined for thefailed fan. For example, when fan control subsystem 300 detects a fanfailure, fan control subsystem 300 may cause all of the operational fans210 to increase in fan speed based on the fan importance factor of thefailed fan. In certain embodiments, the fan speed of each operationalfan 210 may be increased by multiplying a current fan speed of eachoperational fan by the normalized fan importance factor of the failedfan. Thus, for example, when fan 210-6 fails, fan control subsystem 300may cause the operational fans 210 (e.g., fans 210-1 through 210-5) toeach automatically increase by a factor of 1.57, the normalized fanimportance factor of fan 210-6. When other fans fail, the fan speedincrease may be more or less than 1.57 depending on the fan importancefactor of the failed fan. For example, when fan 210-5 fails, fan controlsubsystem 300 may direct each of the operational fans remaining (e.g.,fans 210-1 through 210-4 and fan 210-6) to automatically increase in fanspeed by a factor of 1.71, the normalized fan importance factor of fan210-5. Because fan 210-5 is more important than fan 210-6, the failureof fan 210-5 causes a more impactful response than a failure of fan210-6.

In certain embodiments, fan control subsystem 300 may determine anominal volumetric airflow associated with cooling information handlingsystem 200 when all fans 210 are operational. For example, fan controlsubsystem 300 may access information indicative of a nominal magnitudeof airflow 208, expressed in units of air volume over units of time,associated with nominal operation of information handling system 200before any fan 210 has failed. Fan control subsystem 300 mayautomatically detect the nominal volumetric airflow information using asensor that measures airflow or may receive the information from a user.In response to detecting a fan failure, fan control subsystem 300 mayregulate airflow 208 at least in part by automatically increasing thefan speed of the operational fans 210 based on their individual fanimportance factors. In certain embodiments, fan control subsystem 300may increase the fan speed of each operational fan 210 by its normalizedfan importance factor until a dynamically measured actual volumetricairflow matches the nominal volumetric airflow. Specifically, when fan210-3 fails, the fan speed of fan 210-1 may be multiplied by 1.57, thefan speed of fan 210-2 may be multiplied by 2.14, the fan speed of fan210-4 may be multiplied by 1.00 (i.e. remain unchanged), the fan speedof fan 210-5 may be multiplied by 1.71, and the fan speed of fan 210-6may be multiplied by 1.57, according to normalized fan importancefactors of each fan 210 in normalized fan importance factor row 428. Inother examples, each fan may be increased by greater or lessor factors,although the increase of each fan relative to the others may still bebased on the fan importance factors of each fan. Fan control subsystem300 may cause the fan speeds of operational fans 210 to remain elevatedaccording to their fan importance factors at least as long as fancontrol subsystem 300 determines that the actual volumetric airflow isless than the nominal volumetric airflow.

In certain embodiments, regulating the airflow in response to detectingthat a fan has failed may include directing that a thermalcharacteristic of a thermal region associated with the failed fan bealtered based on the fan importance factors and/or relative importancerankings of the failed fan and/or the operational fans. Fan controlsubsystem 300 may direct that the thermal characteristic of the thermalregion be altered in any suitable way. For example, in certainembodiments, fan control subsystem 300 may direct a user to swap athermal component in the thermal region with a thermal component in adifferent thermal region. In the same or other embodiments, fan controlsubsystem 300 may direct the thermal component to be removed from thethermal region. In the same or other embodiments, fan control subsystem300 may automatically direct the thermal component to consume lesspower. In the same or other embodiments, fan control subsystem 300 maydirect that the thermal characteristic of the thermal region be alteredby other means that may suit the particular embodiments.

For example, when fan 210-2 is detected to fail, fan control subsystem300 may direct that large dynamic card 230 be swapped with mediumdynamic card 228 based on the high fan importance factor of fan 210-2and the lower fan importance factors for the fans 210 associated withmedium dynamic card 228 (i.e. fans 210-3, 210-4, and 210-5). In otherexamples, fan control subsystem 300 may direct that dynamic card 230 beremoved from first thermal region 212-2 or fan control subsystem 300 mayautomatically direct that dynamic card 230 consume less power, forexample by switching dynamic card 230 into a low power state. In yetother examples, large dynamic card 230 may be moved away from thermalregion 212-2 to another socket adapted to receive large dynamic card 230(not shown). It is noted that large dynamic card 230 and thermal region212-2 are used as examples only, and that any thermal component within athermal region associated with a failed fan may be swapped, removed, orpowered down to alter the thermal characteristic of the thermal regionassociated with the failed fan.

In addition or as an alternative to regulating the airflow as describedin relation to the various embodiments above, fan control subsystem 300may also regulate performance of an information handling system bylimiting power to certain thermal components. For example, a closed loopthermal component (e.g., a high priority component such as a processor)may be active in a thermal region after a fan associated with thethermal region fails. In response to the fan failure, the thermalcomponent may be preemptively power limited in anticipation that thethermal component will increase in temperature. However, because thethermal component is closed loop, the thermal component may cause fansfrom neighboring thermal regions to increase in fan speed independentlyof fan control subsystem 300 as the thermal component increases intemperature. Accordingly, fan control subsystem 300 may at leasttemporarily abstain from limiting the power of the thermal component.Specifically, fan control subsystem 300 may determine that a thermalmargin exists between the current temperature of the thermal componentand a maximum temperature for the thermal component (e.g., a maximumrated temperature specified by a manufacturer of the thermal component,a characterized temperature at which the thermal component may fail, atemperature budgeted for the thermal component in a thermal plan, etc.).When the thermal margin is detected, fan control subsystem 300 mayabstain from preemptive power limiting of the thermal component whilecontinuing to monitor the temperature of the thermal component. In someexamples, operational fans being controlled by the closed loop of thethermal component independently from fan control subsystem 300 may allowthe thermal component to maintain the thermal margin indefinitely. Assuch, fan control subsystem 300 may continuously abstain from limitingpower to the thermal component. In other examples, fan control subsystem300 may eventually detect that the thermal component lacks a sufficientthermal margin. Here, fan control subsystem 300 may progressively limitpower to the thermal component such that the thermal component receivesis only limited in power in proportion to an increase of the currenttemperature of the thermal component. For example, fan control subsystem300 may limit power to the thermal component such that the thermalcomponent receives as much power as possible without exceeding themaximum temperature for the thermal component.

Referring now to FIG. 5, a flowchart of selected elements of anembodiment of method 500 for regulating airflow and performance in aninformation handling system after fan failure is depicted. Method 500may be performed by any suitable apparatus or system, such as fancontrol subsystem 300 (see FIG. 3). It is noted that certain operationsdescribed in method 500 may be optional or may be rearranged indifferent embodiments.

Method 500 may begin at step 502 by determining a first fan importancefactor of a first fan associated with a first thermal region of aninformation handling system. The first fan importance factor may bereceived from a user of the information handling system or may becomputed automatically. The first fan importance factor may be based ona presence of one or more thermal components in a thermal region of theinformation handling system associated with the first fan. For example,a fan associated with a thermal region having many thermal componentsmay have a relatively high fan importance factor while a fan associatedwith a thermal region having few thermal components may have arelatively low fan importance factor. The first fan importance factormay also be based on thermal priority ratings of each of the one or morethermal components in the thermal region. For example, a fan associatedwith a thermal region having components with high thermal priorityratings may have a relatively high fan importance factor while a fanassociated with a thermal region having components with low thermalpriority ratings may have a relatively low fan importance factor.Determining the first fan importance factor may be performed inaccordance with the examples given above in relation to FIGS. 4A, 4B,and 4C.

At step 504, method 500 may determine a second fan importance factor ofa second fan associated with a second thermal region of an informationhandling system. As with the first fan importance factor, the second fanimportance factor may be received from a user of the informationhandling system or may be computed automatically. The second fanimportance factor may be based on a presence of one or more thermalcomponents in a thermal region of the information handling systemassociated with the second fan. The second fan importance factor mayalso be based on thermal priority ratings of each of the one or morethermal components in the thermal region. Determining the second fanimportance factor may be performed in accordance with the examples givenabove in relation to FIGS. 4A, 4B, and 4C.

At step 506, method 500 may detect a failure of the first fan. Asdescribed above in relation to FIG. 4C, the fan failure may occur due tovarious circumstances and may be detrimental to operations and/orperformance of the information handling system for various reasons. Thedetection of the failure of the first fan may be performed in anysuitable way, as described above. For example, the fan failure may beautomatically detected by the presence or absence of a communicationwith the failed fan. In other examples, a user of the informationhandling system may provide input indicative of the fan failure.

In response to detecting the failure of the first fan at step 506,method 500 may proceed to step 508. At step 508, method 500 may regulateairflow based on the first fan importance factor, based on the secondfan importance factor, or based on a combination of both fan importancefactors. Regulating the airflow based on the fan importance factorsdetermined at steps 502 and/or 504 may be performed in any suitable way.For example, several embodiments for regulating the airflow in theinformation handling system based on fan importance factors aredescribed above in relation to FIG. 4C. In certain embodiments, a userof the information handling system may be directed to swap the first fan(i.e., the failed fan) with the second fan (i.e. an operational fan)based on the fan importance factors of both the first fan and the secondfan. This embodiment is described in more detail above. In the same orother embodiments, the airflow in the information handling system may beregulated by increasing the fan speed of the second fan (i.e. anoperational fan) based on the fan importance factor of the first fan(i.e. the failed fan). This embodiment is described in more detailabove. In the same or other embodiments, a nominal volumetric airflowassociated with cooling the information handling system when all fansare operational is determined. The airflow in the information handlingsystem may be regulated by automatically increasing the fan speed of thesecond fan (i.e. an operational fan) according to the fan importancefactor of the second fan as long as an actual volumetric airflow is lessthan the nominal volumetric airflow. This embodiment is described inmore detail above. In the same or other embodiments, the airflow of theinformation handling system may be regulated by directing that a thermalcharacteristic of the thermal region associated with the first fan (i.e.the failed fan) be altered based on the first fan importance factorand/or the second fan importance factor. This embodiment is described inmore detail above. After regulating the airflow in the informationhandling system, method 500 may end.

As disclosed herein, a fan control subsystem may control a plurality offans in an information handling system to cool the information handlingsystem. The fan control subsystem may determine a fan importance factorfor each of the plurality of fans based on the presence and thermalpriority ratings of one or more thermal components located in arespective thermal region associated with each of the plurality of fans.Upon detecting a failure of one of the plurality of fans, the fancontrol subsystem may regulate airflow within the information handlingsystem based on the fan importance factors determined for the fans.

The above disclosed subject matter is to be considered illustrative, andnot restrictive, and the appended claims are intended to cover all suchmodifications, enhancements, and other embodiments which fall within thetrue spirit and scope of the present disclosure. Thus, to the maximumextent allowed by law, the scope of the present disclosure is to bedetermined by the broadest permissible interpretation of the followingclaims and their equivalents, and shall not be restricted or limited bythe foregoing detailed description.

What is claimed is:
 1. A method for regulating airflow in an informationhandling system, comprising: determining a first fan importance factorof a first fan of the information handling system, the first fanimportance factor being indicative of a relative importance of the firstfan in cooling the information handling system as compared to a secondfan; determining a second fan importance factor of the second fan of theinformation handling system, the second fan importance factor beingindicative of a relative importance of the second fan in cooling theinformation handling system as compared to the first fan; detecting, bya fan control subsystem, a failure of the first fan; and regulating, bythe fan control subsystem in response to detecting the failure of thefirst fan, airflow in the information handling system based on at leastone of the first fan importance factor and the second fan importancefactor.
 2. The method of claim 1, wherein: determining the first fanimportance factor comprises computing the first fan importance factordependent on a first thermal priority rating indicative of a priority ofcooling a first thermal component of the information handling systemthat is cooled, at least in part, by the first fan; determining thesecond fan importance factor comprises computing the second fanimportance factor dependent on a second thermal priority ratingindicative of a priority of cooling a second thermal component of theinformation handling system that is cooled, at least in part, by thesecond fan.
 3. The method of claim 2, wherein: the first fan isassociated with a first thermal region of the information handlingsystem; the second fan is associated with a second thermal region of theinformation handling system; computing the first fan importance factoris further dependent on information indicative of the presence of thefirst thermal component in the first thermal region; computing thesecond fan importance factor is further dependent on informationindicative of the presence of the second thermal component in the secondthermal region.
 4. The method of claim 1, wherein: the first fan isassociated with a first thermal region of the information handlingsystem; the second fan is associated with a second thermal region of theinformation handling system; regulating the airflow in the informationhandling system comprises: determining, dependent on the first fanimportance factor and the second fan importance factor, that a thermalcharacteristic of the first thermal region is to be altered; directingthat the thermal characteristic of the first thermal region be altered;directing that the thermal characteristic of the first thermal region bealtered comprises at least one of: directing a user to swap the firstfan with the second fan; directing a user to remove a first thermalcomponent from the first thermal region; and directing a user to swap afirst thermal component in the first thermal region with a secondthermal component in the second thermal region.
 5. The method of claim1, wherein regulating the airflow in the information handling systemcomprises: automatically increasing a fan speed of the second fan by anamount based on the first fan importance factor; automaticallyincreasing a fan speed of the second fan by an amount based on thesecond fan importance factor; or automatically decreasing a powerconsumption of a first thermal component of the information handlingsystem that is cooled, at least in part, by the first fan.
 6. The methodof claim 1, wherein: determining the first fan importance factorcomprises retrieving the first fan importance factor from a memory, thefirst fan importance factor having been previously computed dependent ona first thermal priority rating indicative of a priority of cooling afirst thermal component of the information handling system that iscooled, at least in part, by the first fan; determining the second fanimportance factor comprises retrieving the second fan importance factorfrom a memory, the second fan importance factor having been previouslycomputed dependent on a second thermal priority rating indicative of apriority of cooling a second thermal component of the informationhandling system that is cooled, at least in part, by the second fan. 7.The method of claim 1, wherein the information handling system comprisesthe fan control subsystem.
 8. An article of manufacture, comprising: anon-transitory machine-readable medium; and instructions stored on thenon-transitory machine-readable medium that, when read and executed by aprocessor, cause the processor to: determine a first fan importancefactor of a first fan of an information handling system, the first fanimportance factor being indicative of a relative importance of the firstfan in cooling the information handling system as compared to a secondfan; determine a second fan importance factor of the second fan of theinformation handling system, the second fan importance factor beingindicative of a relative importance of the second fan in cooling theinformation handling system as compared to the first fan; detect afailure of the first fan; and regulate, in response to detecting thefailure of the first fan, airflow in the information handling systembased on at least one of the first fan importance factor and the secondfan importance factor.
 9. The article of claim 8, wherein: to determinethe first fan importance factor, the instructions further cause theprocessor to compute the first fan importance factor dependent on afirst thermal priority rating indicative of a priority of cooling afirst thermal component of the information handling system that iscooled, at least in part, by the first fan; to determine the second fanimportance factor, the instructions further cause the processor tocompute the second fan importance factor dependent on a second thermalpriority rating indicative of a priority of cooling a second thermalcomponent of the information handling system that is cooled, at least inpart, by the second fan.
 10. The article of claim 9, wherein: the firstfan is associated with a first thermal region of the informationhandling system; the second fan is associated with a second thermalregion of the information handling system; computation of the first fanimportance factor is further dependent on information indicative of thepresence of the first thermal component in the first thermal region;computation of the second fan importance factor is further dependent oninformation indicative of the presence of the second thermal componentin the second thermal region.
 11. The article of claim 8, wherein: thefirst fan is associated with a first thermal region of the informationhandling system; the second fan is associated with a second thermalregion of the information handling system; to regulate the airflow inthe information handling system, the instructions further cause theprocessor to: determine, dependent on the first fan importance factorand the second fan importance factor, that a thermal characteristic ofthe first thermal region is to be altered; direct that the thermalcharacteristic of the first thermal region be altered; to direct thatthe thermal characteristic of the first thermal region be altered, theinstructions further cause the processor to: direct a user to swap thefirst fan with the second fan; direct a user to remove a first thermalcomponent from the first thermal region; or direct a user to swap afirst thermal component in the first thermal region with a secondthermal component in the second thermal region.
 12. The article of claim8, wherein to regulate the airflow in the information handling system,the instructions further cause the processor to: automatically increasea fan speed of the second fan by an amount based on the first fanimportance factor; automatically increase a fan speed of the second fanby an amount based on the second fan importance factor; or automaticallydecrease a power consumption of a first thermal component of theinformation handling system that is cooled, at least in part, by thefirst fan.
 13. The article of claim 8, wherein: to determine the firstfan importance factor, the instructions further cause the processor toretrieve the first fan importance factor from a memory, the first fanimportance factor having been previously computed dependent on a firstthermal priority rating indicative of a priority of cooling a firstthermal component of the information handling system that is cooled, atleast in part, by the first fan; to determine the second fan importancefactor, the instructions further cause the processor to retrieve thesecond fan importance factor from a memory, the second fan importancefactor having been previously computed dependent on a second thermalpriority rating indicative of a priority of cooling a second thermalcomponent of the information handling system that is cooled, at least inpart, by the second fan.
 14. The article of claim 8, wherein theinformation handling system comprises the processor.
 15. An informationhandling system, comprising: a first fan configured to cool a firstthermal component of the information handling system; a second fanconfigured to cool a second thermal component of the informationhandling system; a processor; and a non-transitory machine-readablemedium comprising instructions that, when read and executed by theprocessor, cause the processor to: determine a first fan importancefactor of a first fan of an information handling system, the first fanimportance factor being indicative of a relative importance of the firstfan in cooling the information handling system as compared to a secondfan; determine a second fan importance factor of the second fan of theinformation handling system, the second fan importance factor beingindicative of a relative importance of the second fan in cooling theinformation handling system as compared to the first fan; detect afailure of the first fan; and regulate, in response to detecting thefailure of the first fan, airflow in the information handling systembased on at least one of the first fan importance factor and the secondfan importance factor.
 16. The information handling system of claim 15,wherein: to determine the first fan importance factor, the instructionsfurther cause the processor to compute the first fan importance factordependent on a first thermal priority rating indicative of a priority ofcooling the first thermal component of the information handling system;to determine the second fan importance factor, the instructions furthercause the processor to compute the second fan importance factordependent on a second thermal priority rating indicative of a priorityof cooling the second thermal component of the information handlingsystem.
 17. The information handling system of claim 16, wherein: thefirst fan is associated with a first thermal region of the informationhandling system; the second fan is associated with a second thermalregion of the information handling system; computation of the first fanimportance factor is further dependent on information indicative of thepresence of the first thermal component in the first thermal region;computation of the second fan importance factor is further dependent oninformation indicative of the presence of the second thermal componentin the second thermal region.
 18. The information handling system ofclaim 15, wherein: the first fan is associated with a first thermalregion of the information handling system; the second fan is associatedwith a second thermal region of the information handling system; toregulate the airflow in the information handling system, theinstructions further cause the processor to: determine, dependent on thefirst fan importance factor and the second fan importance factor, that athermal characteristic of the first thermal region is to be altered;direct that the thermal characteristic of the first thermal region bealtered; to direct that the thermal characteristic of the first thermalregion be altered, the instructions further cause the processor to:direct a user to swap the first fan with the second fan; direct a userto remove the first thermal component from the first thermal region; ordirect a user to swap the first thermal component in the first thermalregion with the second thermal component in the second thermal region.19. The information handling system of claim 15, wherein to regulate theairflow in the information handling system, the instructions furthercause the processor to: automatically increase a fan speed of the secondfan by an amount based on the first fan importance factor; automaticallyincrease a fan speed of the second fan by an amount based on the secondfan importance factor; or automatically decrease a power consumption ofthe first thermal component of the information handling system.
 20. Theinformation handling system of claim 15, wherein: to determine the firstfan importance factor, the instructions further cause the processor toretrieve the first fan importance factor from a memory, the first fanimportance factor having been previously computed dependent on a firstthermal priority rating indicative of a priority of cooling a firstthermal component of the information handling system that is cooled, atleast in part, by the first fan; to determine the second fan importancefactor, the instructions further cause the processor to retrieve thesecond fan importance factor from a memory, the second fan importancefactor having been previously computed dependent on a second thermalpriority rating indicative of a priority of cooling a second thermalcomponent of the information handling system that is cooled, at least inpart, by the second fan.